Intercooling system Intercooler with charge-air temperature control Intensive intercooling is the basic precondition for a high degree of output exploitation. At low load, inten- sive charge-air cooling leads to the formation of white smoke. To prevent this happening, an intercooler with integrated heater is installed. The intercooler consists of two separate sections, the heater portion and the intercooler proper. There is a constant flow of engine coolant through the heater portion, the intercooler proper being supplied with cold raw water only if necessary. Control is via the charge-air pressure.
At low load and correspondingly low charge-air pressure, cold raw water is channelled past the intercooler via a bypass by means of an annular slide valve. At increased out- put and higher charge-air pressure, the annular slide valve closes the bypass, so that raw water now flows through the intercooler. Owing to this arrangement, the charge−air temperature is controlled as a function of the engine load in the following way: At low load the following temperature situations occur: D Charge-air temperature upstream of intercooler: 20 ° C to 45 ° C, depending on the temperature in the en- gine room. D Engine coolant temperature approx. 80 ° C, the thermostat is closed.
D Charge-air temperature downstream of the intercooler: approx. 70 ° C, ie charge air is pre−heated and the formation of white smoke prevented. D Charge-air temperature upstream of intercooler: approx. 200 ° C D Engine coolant temperature: 80 ° C to 90 ° C, the thermostat is open. D Raw water temperature _ C D Charge-air temperature downstream of the intercooler: approx. 50 ° C, ie the charge air is cooled − a pre- condition for high engine output At full load the following temperature situations occur:
Flow at idle speed and low load Flow at full load 1 2 1 2 3 4 3 7 7 8 8 70 _ C 200 _ C 20 _ C 50 _ C 4 5 5 6 6 1 Intercooler portion 2 Heater portion 3 Engine coolant outlet 4 Raw water outlet 5 Engine coolant intake 6 Raw water intake 7 Charge-air intake 8 Charge-air outlet 25